Neuroimaging correlates of aggression in schizophrenia: an update

Task-related brain activation associated with violence in patients with schizophrenia: A meta-analysis

This study investigates specific changes in brain function during cognitive and emotional tasks in patients with schizophrenia and a history of violence (VSCZ) compared with non-violent patients with schizophrenia and healthy controls. A comprehensive literature search was conducted at the Web of Science, Medline, and PubMed. Ten studies met the inclusion criteria. In which, eight studies compared brain activation between patients with VSCZ and non-violent patients with schizophrenia, and the former exhibited increased activation at the middle occipital gyrus and rectus compared with the latter. Seven studies compared brain activation between patients with VSCZ and controls, and the former exhibited increased activation at the anterior cingulate cortex, cerebellum VI region, lingual gyrus and fusiform. Subgroup analysis in five studies performing emotional tasks revealed that patients with VSCZ showed increased activation at the middle occipital gyrus compared with non-violent patients with schizophrenia. Our findings suggest that abnormal emotion perception and regulation significantly contribute to the increased risk of violence in patients with schizophrenia. Notably, the middle occipital gyrus and rectus emerge as key neurophysiological correlates associated with this phenomenon.

Peak alpha frequency and electroencephalographic microstates are correlated with aggression in schizophrenia

Large scale retrospective studies have shown an association between schizophrenia and risk of violence. Overall, this increase in risk is small and does not justify or support stigmatizing public perceptions or media depictions of people with schizophrenia. Nonetheless, in some situations, some symptoms of schizophrenia can increase the risk of violent behavior. Prediction of this behavior would allow high impact preventive interventions. However, to date the neurobiological correlates of violent behavior in schizophrenia are not well understood, precluding the development of prognostic biomarkers. We used electroencephalography to measure alpha activity and microstates from 31 patients with schizophrenia and 18 age matched controls. Participants also completed multiple assessments of current aggressive tendencies and their lifetime history of aggressive acts. We found that individual alpha peak frequency was negatively correlated with aggression scores in both patients and controls (largest Spearman's r = -0.45). Furthermore, this result could be replicated in data taken from a single frontal channel suggesting that this may be possible to obtain in routine clinical settings (largest Spearman's r = -0.40). We also found that transitions between microstates corresponding to auditory and visual networks were inversely correlated with aggression scores. Finally, we found that, within patients, aggression was correlated with the degree of randomness between microstate transitions. This suggests that aggression is related to inappropriate switching between large scale brain networks and subsequent failure to appropriately integrate complicated environmental and internal stimuli. By elucidating some of the electrophysiological correlates of aggression, these data facilitate the development of prognostic biomarkers.

Neuroanatomical correlates of aggressiveness: a case-control voxel- and surface-based morphometric study

Aggression occurs across the population ranging on a symptom continuum. Most previous studies have used magnetic resonance imaging in clinical/forensic samples, which is associated with several confounding factors. The present study examined structural brain characteristics in two healthy samples differing only in their propensity for aggressive behavior. Voxel- and surface-based morphometry (SBM) analyses were performed on 29 male martial artists and 32 age-matched male controls. Martial artists had significantly increased mean gray matter volume in two frontal (left superior frontal gyrus and bilateral anterior cingulate cortex) and one parietal (bilateral posterior cingulate gyrus and precuneus) brain clusters compared to controls (whole brain: p < 0.001, cluster level: family-wise error (FWE)-corrected). SBM analyses revealed a trend for greater gyrification indices in martial artists compared to controls in the left lateral orbital frontal cortex and the left pars orbitalis (whole brain: p < 0.001, cluster level: FWE-corrected). The results indicate brain structural differences between martial artists and controls in frontal and parietal brain areas critical for emotion processing/inhibition of emotions as well as empathic processes. The present study highlights the importance of studying healthy subjects with a propensity for aggressive behavior in future structural MRI research on aggression.

Aberrant brain structure in patients with schizophrenia and violence: A meta-analysis

Previous studies have indicated that schizophrenia is associated with an increased risk of violence, which may constitute a public health concern, leading to poor treatment outcomes and stigmatization of patients. Investigating brain structural features of violence in schizophrenia could help us understand its specific pathogenesis and find effective biomarkers. Our study aimed at identifying reliable brain structural changes associated with violence in patients with schizophrenia by conducting a meta-analysis and meta-regression of magnetic resonance imaging studies. Specific brain changes in patients with schizophrenia and violence (VSZ) were studied, compared with patients with schizophrenia and violence (VSZ), patients with non-violent schizophrenia (NVSZ), and individuals with a history of violence only and health controls. Primary outcomes revealed that there was no significant difference of gray matter volume between patients with VSZ and patient with NVSZ. Compared with controls, patients with VSZ exhibited decreased gray matter volume in the insula, the superior temporal gyrus (STG), the left inferior frontal gyrus, the left parahippocampus, and the right putamen. Compared with individuals with a history of violence only, patients with VSZ exhibited decreased volume in the right insula and the right STG. Meta-regression analysis revealed a negative correlation between the duration of schizophrenia and the volume of the right insula in patients with VSZ. These findings may suggest a shared neurobiological basis for both violence and psychiatric symptoms. The impaired frontotemporal-limbic network may serve as a neurobiological basis for higher prevalence of violent behaviour in patients with schizophrenia. However, it is important to note that these changes are not unique to patients with VSZ. Further investigation is needed to explore the neural mechanism that drive the interaction between violent behaviour and specific aggression-related dimensions of schizophrenia.

Violence in relation to cognitive deficits and symptom severity in a sample of Egyptian patients with schizophrenia

BACKGROUND

Patient with schizophrenia are significantly more likely to be violent than general population; and the consequences of this violence risk are often very serious for the patients, their caregivers, and the entire community.

AIM

To assess the risk of violence in patients with schizophrenia and its correlation with severity of symptoms and cognitive functions.

METHODS

A cross-sectional comparative study conducted in Okasha institute of psychiatry including 50 patients with schizophrenia compared to 50 healthy control group regarding violence risk as assessed by Historical, Clinical, and Risk Management-20 (HCR-20), case group was assessed using Structured Clinical Interview for DSM-IV (SCID-I), Positive and Negative Syndrome Scale (PANSS), cognitive functions were assessed by Wechsler Adult Intelligence Scale (WAIS), Trail Making Test (TMT) Part A and B, the Wisconsin Card Sorting Test (WCST), and the Wechsler Memory Scale (WMS).

RESULTS

There was a statistically significant difference between case and control groups regarding risk of violence where 58% of the case group were found to have risk of violence compared to only 18% in the control group. There was a significant correlation between this risk of violence and period of untreated psychosis, no of episodes, and history of substance use; also was significantly correlated with PANSS and Wisconsin card sorting test subscales. Regarding logistic regression analysis for factors affecting violence risk; total PANSS score and history of substance use were significant independent factors that increase violence risk.

CONCLUSION

Violence risk in patient with schizophrenia is a cardinal factor that may affect life of the patients, their family, and society; this risk can be affected by different factors including severity of symptoms, no of episodes, history of substance use, and cognitive function of the patients.

Structural Deficits in the Frontotemporal Network Associated With Psychopathic Traits in Violent Offenders With Schizophrenia

People with schizophrenia (SZ) are at increased risk of violence compared to the general population. However, the neural mechanisms of violent behavior in patients with SZ are still unclear due to the heterogeneity of the diseased population. In this study, we aimed to examine the neural correlates of violent behavior in SZ and to determine whether the structural deficits were related to psychopathic traits. A total of 113 participants, including 31 SZ patients with violent behavior (vSZ), 39 SZ patients without violent behavior (nvSZ), and 43 healthy controls (HC), completed the T1-weighted magnetic resonance imaging (MRI) scan and were analyzed using voxel-based morphometry approach. The psychopathic traits were assessed using the Psychopathy Checklist: Screening Version (PCL:SV). The results showed decreased gray matter volume (GMV) in the vSZ group in the right temporal lobe and bilateral inferior frontal gyri compared to HCs; while reduced GMV in the inferior parietal lobe, parahippocampal and orbital frontal gyri was found in the nvSZ group compared with HCs. Correlation analyses showed that psychopathic traits were negatively associated with the GMV in the right superior temporal and left fusiform gyri in the vSZ group, indicating that psychopathic traits, as reflected by the score of antisocial factor, might be related to structural deficits in the temporal lobe, which led to a propensity to violent behavior in patients with SZ. Our findings suggest that violent behavior in patients with SZ might have a personality background associated with the frontotemporal network aberrance. In future studies, we need to take a closer look at psychopathic traits for better understanding of the mechanism of interpersonal violence in patients with SZ and to explore whether the imaging findings from this study can serve as a biomarker to predict future violent behaviors and community living.

Brain gray matter differences among forensic psychiatric patients with psychosis and incarcerated individuals without psychosis: A source-based morphometry study

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We employed source-based morphometry to examine grey matter differences in forensic psychiatric patients with psychosis versus incarcerated controls without psychosis.

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Compared to the psychotic group, the non-psychotic group demonstrated greater loading weights in the superior, transverse, and middle temporal gyrus and the anterior cingulate.

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Compared to the non-psychotic group, the psychotic group exhibited greater loading weights in the frontal pole, precuneus, basal ganglia, thalamus, parahippocampal gyrus, and visual cortex.

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Neuroimaging investigations of offenders with psychosis ought to control for the level of psychopathic traits present.

Background

While psychosis is a risk factor for violence, the majority of individuals who perpetrate aggression do not present psychotic symptoms. Pathological aggressive behavior is associated with brain gray matter differences, which, in turn, has shown a relationship with increased psychopathic traits. However, no study, to our knowledge, has ever investigated gray matter differences in forensic psychiatric patients with psychosis compared with incarcerated individuals without psychosis matched on levels of psychopathic traits. Here, we employed source-based morphometry (SBM) to investigate gray matter differences in these two populations.

Methods

We scanned 137 participants comprising two offender subgroups: 69, non-psychotic incarcerated offenders and 68, psychotic, forensic psychiatric patients. Groups showed no difference in age, race, ethnicity, handedness, and Hare Psychopathy Checklist-Revised scores. Source-based morphometry was utilized to identify spatially distinct sets of brain regions where gray matter volumes covaried between groups. SBM is a data-driven, multivariate technique that uses independent components analysis to categorize groups of voxels that display similar variance patterns (e.g., components) that are compared across groups.

Results

SBM identified four components that differed between groups. These findings indicated greater loading weights in the superior, transverse, and middle temporal gyrus and anterior cingulate in the non-psychotic versus psychotic group; greater loading weights in the basal ganglia in the psychotic versus non-psychotic group; greater loading weights in the frontal pole, precuneus, and visual cortex among psychotic versus non-psychotic offenders; and greater loading weights in the thalamus and parahippocampal gyrus in psychotic versus non-psychotic groups.

Conclusions

Two different offender groups that perpetrate violence and show comparable levels of psychopathic traits evidenced different gray matter volumes. We suggest that future studies of violent offenders with psychosis take psychopathic traits into account to refine neural phenotypes.

Aggressiveness is associated with excitement on the five-factor model of the positive and negative syndrome scale and prefrontal function in patients with stable schizophrenia

Aggressiveness is a clinical concern in the stable phase of schizophrenia, as well as in the acute phase. The factors that affect aggressiveness during the stable phase remain unclear. This study investigated factors associated with aggressiveness in patients with stable schizophrenia. Sixty-six patients with schizophrenia who were in the stable phase without acute exacerbation were assessed for aggressiveness using the Buss-Perry Aggression Questionnaire; impulsivity using the Barratt Impulsiveness Scale Version 11, psychotic symptoms using the five-factor model of the Positive and Negative Syndrome Scale (PANSS) including positive symptoms, negative symptoms, disorganization, excitement, and emotional distress; and prefrontal hemodynamic responses using near-infrared spectroscopy. Multivariate regression analyses showed that the excitement factor of the PANSS five-factor model, which comprised four PANSS items (poor impulse control, hyperactivity, hostility, and uncooperativeness), and delayed prefrontal hemodynamic responses were associated with elevated aggressiveness. These findings suggest that in patients with stable schizophrenia, excitement symptoms and prefrontal dysfunction are associated with elevated aggressiveness. Furthermore, the impact of impulsive traits on aggressiveness is less relevant. Our results shed light on a specific aspect of aggressiveness in patients with stable schizophrenia and may indicate factors to consider in the clinical setting.

Violent Behavior Is Associated With Emotion Salience Network Dysconnectivity in Schizophrenia

Background: Despite individuals with schizophrenia being at an elevated risk of violence compared to the general population, limited efforts have been invested in investigating the neurobiological etiology explaining the increase. Among the few studies examining functional disruptions pertaining to violent schizophrenia patients using fMRI, only one study has considered functional connectivity. The current state of knowledge does not allow to infer deficits in functional connectivity specific to distinct cognitive/emotional states that have been associated with the emergence of violence in schizophrenia, such as negative emotion processing. This study sought to identify disrupted connectivity among men with schizophrenia and a history of violence (SCZ+V), compared to men with schizophrenia without a history of violence (SCZ-V) and healthy controls, during negative emotion processing using fMRI. Methods: Twenty SCZ+V, 19 SCZ-V, and 21 healthy men were scanned while viewing negative images. Results: Negative images elicited an increased connectivity between the dorsal anterior cingulate cortex (dACC) and the bilateral rostral prefrontal cortex (rPFC), as well as a decreased functional connectivity between the frontal regions (bilateral rPFC and dACC) and the putamen and hippocampus in SCZ+V men as compared to SCZ-V men and healthy controls. Concurrently, the centrality of the dACC within the network was reduced in SCV+V subjects. Conclusions: These results suggest an inefficient integration of the information by the dACC between frontal and limbic regions in SCZ+V men during negative emotion processing and highlight the importance of the ACC in the neurobiological bases of violent behavior in schizophrenia.

RBFOX1, encoding a splicing regulator, is a candidate gene for aggressive behavior

The RBFOX1 gene (or A2BP1) encodes a splicing factor important for neuronal development that has been related to autism spectrum disorder and other neurodevelopmental phenotypes. Evidence from complementary sources suggests that this gene contributes to aggressive behavior. Suggestive associations with RBFOX1 have been identified in genome-wide association studies (GWAS) of anger, conduct disorder, and aggressive behavior. Nominal association signals in RBFOX1 were also found in an epigenome-wide association study (EWAS) of aggressive behavior. Also, variants in this gene affect temporal lobe volume, a brain area that is altered in several aggression-related phenotypes. In animals, this gene has been shown to modulate aggressive behavior in Drosophila. RBFOX1 has also been associated with canine aggression and is upregulated in mice that show increased aggression after frustration of an expected reward. Associated common genetic variants as well as rare duplications and deletions affecting RBFOX1 have been identified in several psychiatric and neurodevelopmental disorders that are often comorbid with aggressive behaviors. In this paper, we comprehensively review the cumulative evidence linking RBFOX1 to aggression behavior and provide new results implicating RBFOX1 in this phenotype. Most of these studies (genetic and epigenetic analyses in humans, neuroimaging genetics, gene expression and animal models) are hypothesis-free, which strengthens the validity of the findings, although all the evidence is nominal and should therefore be taken with caution. Further studies are required to clarify in detail the role of this gene in this complex phenotype.

Volumetric Abnormalities in Violent Schizophrenia Patients on the General Psychiatric Ward

BACKGROUND

In recent years, neuroimaging has been used increasingly to explore the biological underpinnings of violence carried out by schizophrenia patients (SPs). Studies have focused mostly on patients with a history of carrying out severe physical assaults, or comorbid with substance abuse/personality disorder (SA/PD). As a result, participants were unrepresentative and the interpretation of brain-structure changes was confusing. Here, we concentrated on SPs on a general psychiatric ward with a history of relatively lower violence, and individuals comorbid with SA or PD were excluded. We expected to identify the characteristics of brain morphometry in this population, and to explore whether the morphometric changes were universal.

METHODS

Forty-eight violent schizophrenia patients (VSPs), twenty-seven non-VSPs (nVSPs) and 28 nonviolent healthy controls (HCs) were investigated. Voxel-based morphometry was used to evaluate the gray matter volume (GMV) of all study participants. Whole-brain analyses were used to reveal group effects and differences between any two groups. Correlation analyses were undertaken between significant brain regions and behavioral measurements in the VSP group.

RESULTS

Patients showed a significantly smaller GMV in widespread frontal, temporal, and limbic regions compared with HCs. No region was found in which the two patient groups had significantly larger volumes compared with that in HCs. A significant decrease in the GMV of the right fusiform gyrus was found in the VSP group compared with that in the nVSP group (p = 0.004), where the GMV of this region had a negative correlation with the Physical Aggression [subscale of the Modified Overt Aggression Scale (MOAS)] or Hostility score. The VSP group showed a trend of GMV decrease in the left middle temporal cortex compared with that in the nVSP group (p = 0.077). Negative correlation was also found between the GMV of left inferior temporal gyrus/left Superior frontal gyrus, medial and the Hostility score.

CONCLUSIONS

Our results provide initial evidence demonstrating the generalizability of GMV abnormalities in SPs engaged in varying levels of violence, even when SA or PD have not been implicated. GMV reduction was correlated with only the Physical Aggression subscale score of the MOAS, suggesting that this change in brain morphology may be dependent upon different types of violent actions.

Biological Aspects of Aggression and Violence in Schizophrenia

Although the majority of patients with schizophrenia are not actually violent, an increased tendency toward violent behaviors is known to be associated with schizophrenia. There are several factors to consider when identifying the subgroup of patients with schizophrenia who may commit violent or aggressive acts. Comorbidity with substance abuse is the most important clinical indicator of increased aggressive behaviors and crime rates in patients with schizophrenia. Genetic studies have proposed that polymorphisms in the promoter region of the serotonin transporter gene and in the catechol-O-methyltransferase gene are related to aggression. Neuroimaging studies have suggested that fronto-limbic dysfunction may be related to aggression or violence. By identifying specific risk factors, a more efficient treatment plan to prevent violent behavior in schizophrenia will be possible. Management of comorbid substance use disorder may help prevent violent events and overall aggression. Currently, clozapine may be the only effective antipsychotic medication to repress aggressive behavior. With the current medical field moving toward tailored medicine, it is important to identify vulnerable schizophrenia populations and provide efficient treatment.

Voxel-Based Morphometry Correlates of an Agitated-Aggressive Syndrome in the At-Risk Mental State for Psychosis and First Episode Psychosis

There are mixed reports on structural neuroimaging correlates of aggression in schizophrenia with weak evidence due to cohort overlaps and lack of replications. To our knowledge, no study examined volumetric neuroimaging correlates of aggression in early stages of psychosis. An agitated-aggressive syndrome is present in at-risk mental state (ARMS) and in first-episode psychosis (FEP) - it is unclear whether this syndrome is associated with structural brain abnormalities in early stages of psychosis. Using three-dimensional magnetic resonance imaging and a whole brain voxel-based morphometry approach, we examined 56 ARMS patients, 55 FEP patients and 25 healthy controls. We operationalized aggression using the Excited Component of the Brief Psychiatric Rating Scale (BPRS-EC) and dichotomized our patient group by median split into "BPRS-EC high" (n = 49) and "BPRS-EC low" groups (n = 62). The "BPRS-EC high" group had significantly smaller left lingual gyrus volume than HC. This finding was not present in the "BPRS-EC low" group. In addition, grey matter volume in the left lingual gyrus showed a negative linear correlation with BPRS-EC over all subjects (ρ = -0.318; p = 0.0001) and in the patient group (ρ = -0.202; p = 0.033). These findings provide first hints on structural brain abnormalities associated with an agitated-aggressive syndrome in ARMS and FEP patients.

Neural networks of aggression: ALE meta-analyses on trait and elicited aggression

There is considerable evidence that emotion dysregulation and self-control impairments lead to escalated aggression in populations with psychiatric disorders. However, convergent quantitative evidence on the neural network explaining how aggression arises is still lacking. To address this gap, peak activations extracted from extant functional magnetic resonance imaging (fMRI) studies were synthesized through coordinate-based meta-analyses. A systematic search in the PubMed database was conducted and 26 fMRI studies met the inclusion criteria. Three separate activation likelihood estimation (ALE) meta-analyses were performed on (1) individual differences in trait aggression (TA) studies, (2) individual differences in TA studies examining executive functioning, and (3) elicited aggression (EA) studies across fMRI behavioral paradigms. Ensuing clusters from ALE meta-analyses were further treated as seeds for follow-up investigations on consensus connectivity networks (CCN) delineated from meta-analytic connectivity modeling (MACM) and resting-state functional connectivity (RSFC) to further characterize their physiological functions. Finally, we obtained a data-driven functional characterization of the ensuing clusters and their networks. This approach offers a boarder view of the ensuing clusters using a boarder network perspective. In TA, aberrant brain activations were found only in the right precuneus. Follow-up analyses revealed that the precuneus seed was within the frontal-parietal network (FPN) associated with action inhibition, visuospatial processing and higher-level cognition. With further restricting to only experiments examining executive functioning, convergent evidence was found in the right rolandic operculum (RO), midcingulate cortex (MCC), precentral gyrus (PrG) and precuneus. Follow-up analyses suggested that RO, MCC and PrG may belong to a common cognitive control network, while the MCC seems to be the hub of this network. In EA, we only revealed a convergent region in the left postcentral gyrus. Follow-up CCN analyses and functional characterizations suggested that this region may also belong to the same cognitive control network found in the TA sub-analysis. Our results suggested that escalated aggression arises from abnormal precuneus activities within the FPN, disrupting the recruitment of other large-scale networks such as adaptive cognitive control network. Consequently, failure to recruit such a network results in an inability to generate adaptive responses, increasing the likelihood of acting aggressively.

Reduced dorsolateral prefrontal cortex activation during affective Go/NoGo in violent schizophrenia patients: An fMRI study

We investigated the influence of anger processing on cognitive control in male schizophrenia patients presenting violent behaviors. We recruited 23 patients without and 24 patients with (SCZ+V) a history of violent behaviors, as well as 22 healthy non-violent men. Participants were administered an affective (angry-neutral faces) Go/NoGo task while undergoing functional magnetic resonance imaging. We found a reduced activation in the dorsolateral prefrontal cortex in SCZ+V patients specifically when inhibiting a response while viewing angry faces. These results show an inability of SCZ+V to recruit a core region of the (inhibitory) cognitive control network in the context of anger.

Predictors of aggression in 3.322 patients with affective disorders and schizophrenia spectrum disorders evaluated in an emergency department setting

INTRODUCTION

The aim of this study is to determine odds of aggression and associated factors in patients with schizophrenia-spectrum disorders (SSD) and affective disorders who were evaluated in an emergency department setting.

METHODS

A retrospective study was conducted using de-identified data from electronic medical records from 3.322 patients who were evaluated at emergency psychiatric settings. Data extracted included demographic information, variables related to aggression towards people or property in the past 6months, and other factors that could potentially impact the risk of aggression, such as comorbid diagnoses, physical abuse and sexual abuse. Bivariate analyses and multivariate regression analyses were conducted to determine the variables significantly associated with aggression.

RESULTS

An initial multivariate regression analysis showed that SSD had 3.1 times the odds of aggression, while bipolar disorder had 2.2 times the odds of aggression compared to unipolar depression. A second regression analysis including bipolar subtypes showed, using unipolar depression as the reference group, that bipolar disorder with a recent mixed episode had an odds ratio (OR) of 4.3, schizophrenia had an OR of 2.6 and bipolar disorder with a recent manic episode had an OR of 2.2. Generalized anxiety disorder was associated with lower odds in both regression analyses.

CONCLUSION

As a whole, the SSD group had higher odds of aggression than the bipolar disorder group. However, after subdividing the groups, schizophrenia had higher odds of aggression than bipolar disorder with a recent manic episode and lower odds of aggression than bipolar disorder with a recent mixed episode.

Differences in Neuropsychological Functioning Between Homicidal and Nonviolent Schizophrenia Samples

Few studies have compared performance on neurocognitive measures between violent and nonviolent schizophrenia samples. A better understanding of neurocognitive dysfunction in violent individuals with schizophrenia could increase the efficacy of violence reduction strategies and aid in risk assessment and adjudication processes. This study aimed to compare neuropsychological performance between 25 homicide offenders with schizophrenia and 25 nonviolent schizophrenia controls. The groups were matched for age, race, sex, and handedness. Independent t-tests and Mann-Whitney U-tests were used to compare the schizophrenia groups' performance on measures of cognition, including composite scores assessing domain level functioning and individual neuropsychological tests. Results indicated the violent schizophrenia group performed worse on measures of memory and executive functioning, and the Intellectual Functioning composite score, when compared to the nonviolent schizophrenia sample. These findings replicate previous research documenting neuropsychological deficits specific to violent individuals with schizophrenia and support research implicating fronto-limbic dysfunction among violent offenders with schizophrenia.

Imaging Violence in Schizophrenia: A Systematic Review and Critical Discussion of the MRI Literature

Background: Persons with schizophrenia have a small but significant increase in risk of violence, which remains after controlling for known environmental risk factors. In vivo MRI-studies may point toward the biological underpinnings of psychotic violence, and neuroimaging has increasingly been used in forensic and legal settings despite unclear relevance. Objectives: (1) To present the first systematic review, following standardized guidelines, of MRI studies of violence with schizophrenia. (2) To critically discuss the promises and pitfalls of using this literature to understand violence in schizophrenia in clinical, forensic, and legal settings. Methods: Following the PRISMA guidelines and literature searches until January 2018, we found 21 original studies that fulfilled the inclusion criteria: (1) Studies of persons with schizophrenia, (2) a history of violence or aggressive behavior, (3) the use of one or more MRI-modalities (sMRI, DTI, fMRI). Results: The most consistent findings from the structural studies were reduced volumes of the hippocampus and the frontal lobe (in particular the orbitofrontal and anterior cingulate cortex) in schizophrenia patients with a history of violence or higher aggression scores. The functional studies mainly showed differences and aggression correlates in the frontal lobe and amygdala. However, the studies were methodologically heterogeneous, with four particular areas of concern: different definitions of violence, region of interest vs. whole-brain studies, small subject samples, and group comparisons in a heterogeneous diagnostic category (schizophrenia). Conclusion: The literature reports subtle, but inconsistent group level differences in brain structure and function associated with violence and aggression with schizophrenia, in particular in areas involved in the formation of psychosis symptoms and affective regulation. Due to methodological challenges the results should be interpreted with caution. In order to come closer to the neurobiological underpinnings of violence in schizophrenia future studies could: (1) address the neurobiological differences of premeditated and reactive violence, (2) use RDoC criteria, for example, or other symptom-based systems to categorize psychosis patients, (3) increase subject cohorts and apply new data driven methods. In this perspective, MRI-studies of violence in schizophrenia have the potential to inform clinical violence prediction and legal evaluations in the future.

Structural Magnetic Resonance Imaging Correlates of Aggression in Psychosis: A Systematic Review and Effect Size Analysis

Background: Aggression in psychoses is of high clinical importance, and volumetric MRI techniques have been used to explore its structural brain correlates. Methods: We conducted a systematic review searching EMBASE, ScienceDirect, and PsycINFO through September 2017 using thesauri representing aggression, psychosis, and brain imaging. We calculated effect sizes for each study and mean Hedge's g for whole brain (WB) volume. Methodological quality was established using the PRISMA checklist (PROSPERO: CRD42014014461). Results: Our sample consisted of 12 studies with 470 patients and 155 healthy controls (HC). After subtracting subjects due to cohort overlaps, 314 patients and 96 HC remained. Qualitative analyses showed lower volumes of WB, prefrontal regions, temporal lobe, hippocampus, thalamus and cerebellum, and higher volumes of lateral ventricles, amygdala, and putamen in violent vs. non-violent people with schizophrenia. In quantitative analyses, violent persons with schizophrenia exhibited a significantly lower WB volume than HC (p = 0.004), and also lower than non-violent persons with schizophrenia (p = 0.007). Conclusions: We reviewed evidence for differences in brain volume correlates of aggression in persons with schizophrenia. Our results point toward a reduced whole brain volume in violent as opposed to non-violent persons with schizophrenia. However, considerable sample overlap in the literature, lack of reporting of potential confounding variables, and missing research on affective psychoses limit our explanatory power. To permit stronger conclusions, further studies evaluating structural correlates of aggression in psychotic disorders are needed.

Functional Neuroimaging Correlates of Aggression in Psychosis: A Systematic Review With Recommendations for Future Research

Background and methods: Aggression in psychosis is clinically important. We systematically compiled the evidence on functional correlates of aggression in psychosis searching PubMed, EMBASE, ScienceDirect, and PsycINFO until September 2017. We included studies reporting functional brain imaging correlates of aggression comparing: (1) affective or non-affective psychosis groups with a history of violence or with aggression operationalized using questionnaires, (2) affective or non-affective psychosis groups with a history of violence or with aggression operationalized using questionnaires to controls, (3) affective or non-affective psychosis groups with a history of violence or with aggression operationalized using questionnaires to controls with diagnoses other than affective or non-affective psychoses. We applied no language restriction and required patients to have a DSM or ICD diagnosis of affective or non-affective psychosis. Results: Our sample consisted of 12 studies with 334 patients and 113 controls. During n-back tasks, violent (VS) as opposed to non-violent persons with schizophrenia (NVS) hypoactivated their inferior parietal lobe. When anticipating shock, VS vs. NVS hyperactivated their medial prefrontal gyrus, cuneus, middle temporal gyrus, and middle occipital gyrus. When viewing negative emotional pictures, VS vs. NVS hyperactivated the middle frontal gyrus, inferior frontal gyrus, anterior cingulate, lingual gyrus, precentral gyrus, globus pallidus, mid-cingulate, and precuneus. Limitations: Due to the small number of available studies, sample overlap, and insufficient reporting of relevant moderators we could not conduct a meta-analysis. Conclusions: We found non-systematic functional correlates of aggression in schizophrenia. Only few studies using varied paradigms and often overlapping samples have been conducted. There have been no attempts to replicate any of the observed findings in the published literature. Focusing on future directions, we recommend that authors adhere to clear definitions of aggression, measurements of psychopathology, comorbidities, and medication. In particular, replication studies would allow for a better synthesis of the findings. PROSPERO Registration Number: CRD42016048579.

Structural brain correlates of interpersonal violence: Systematic review and voxel-based meta-analysis of neuroimaging studies

Owing to inconsistent nomenclature and results, we have undertaken a label-based review and anatomical likelihood estimation (ALE) meta-analysis of studies measuring the quantitative association between regional grey matter (GM) volume and interpersonal violence. Following PRISMA guidelines, we identified studies by searching 3 online databases (Embase, Medline, PsycInfo) and reference lists. Thirty-five studies were included in the label-based review, providing information for 1288 participants and 86 brain regions. Per region, 0-57% of the results indicated significant reductions in GM volume, while 0-23% indicated significant increases. The only region for which more than half of all results indicated significant reductions was the parietal lobe. However, these results were dispersed across subregions. The ALE meta-analysis, which included 6 whole-brain voxel-based morphometry studies totaling 278 participants and reporting 144 foci, showed no significant clusters of reduced GM volume. No material differences were observed when excluding experiments using reactive violence as outcome or subjects diagnosed with psychopathy. Possible explanations for these findings are phenomenological and etiological heterogeneity, and insufficient power in the label-based review and ALE meta-analysis to detect small effects. We recommend that future studies distinguish between subtypes of interpersonal violence, and investigate mediation by underlying emotional and cognitive processes.

Anterior cingulate hyperactivations during negative emotion processing among men with schizophrenia and a history of violent behavior

BACKGROUND

Evidence suggests a 2.1-4.6 times increase in the risk of violent behavior in schizophrenia compared to the general population. Current theories propose that the processing of negative emotions is defective in violent individuals and that dysfunctions within the neural circuits involved in emotion processing are implicated in violence. Although schizophrenia patients show enhanced sensitivity to negative stimuli, there are only few functional neuroimaging studies that have examined emotion processing among men with schizophrenia and a history of violence.

OBJECTIVE

The present study aimed to identify the brain regions with greater neurofunctional alterations, as detected by functional magnetic resonance imaging during an emotion processing task, of men with schizophrenia who had engaged in violent behavior compared with those who had not.

METHODS

Sixty men were studied; 20 with schizophrenia and a history of violence, 19 with schizophrenia and no violence, and 21 healthy men were scanned while viewing positive, negative, and neutral images.

RESULTS

Negative images elicited hyperactivations in the anterior cingulate cortex (ACC), left and right lingual gyrus, and the left precentral gyrus in violent men with schizophrenia, compared to nonviolent men with schizophrenia and healthy men. Neutral images elicited hyperactivations in the right and left middle occipital gyrus, left lingual gyrus, and the left fusiform gyrus in violent men with schizophrenia, compared to the other two groups.

DISCUSSION

Violent men with schizophrenia displayed specific increases in ACC in response to negative images. Given the role of the ACC in information integration, these results indicate a specific dysfunction in the processing of negative emotions that may trigger violent behavior in men with schizophrenia.

Impulsivity and aggression in schizophrenia: a neural circuitry perspective with implications for treatment

Elevations of impulsive behavior have been observed in a number of serious mental illnesses. These phenomena can lead to harmful behaviors, including violence, and thus represent a serious public health concern. Such violence is often a reason for psychiatric hospitalization, and it often leads to prolonged hospital stays, suffering by patients and their victims, and increased stigmatization. Despite the attention paid to violence, little is understood about its neural basis in schizophrenia. On a psychological level, aggression in schizophrenia has been primarily attributed to psychotic symptoms, desires for instrumental gain, or impulsive responses to perceived personal slights. Often, multiple attributions can coexist during a single aggressive incident. In this review, I discuss the neural circuitry associated with impulsivity and aggression in schizophrenia, with an emphasis on implications for treatment. Impulsivity appears to account for a great deal of aggression in schizophrenia, especially in inpatient settings. Urgency, defined as impulsivity in the context of strong emotion, is the primary focus of this article. It is elevated in several psychiatric disorders, and in schizophrenia, it has been related to aggression. Many studies have implicated dysfunctional frontotemporal circuitry in impulsivity and aggression in schizophrenia, and pharmacological treatments may act via that circuitry to reduce urgency and aggressive behaviors; however, more mechanistic studies are critically needed. Recent studies point toward manipulable neurobehavioral targets and suggest that cognitive, pharmacological, neuromodulatory, and neurofeedback treatment approaches can be developed to ameliorate urgency and aggression in schizophrenia. It is hoped that these approaches will improve treatment efficacy.

Val158Met COMT polymorphism and risk of aggression in alcohol dependence

Aggression, violence and antisocial behavior are common in alcoholism, but their biological basis is poorly understood. Several studies and recent meta-analyses indicate that in schizophrenia the catecholamine-O-methyltransferase (COMT) Val158Met genotype may be associated with aggression, most often in methionine allele carriers. We tested this hypothesis in a sample of treatment-seeking alcohol-dependent in-patients (293 German patients and 499 controls, and additional 190 Polish patients as replication sample). As expected, patients with a history of violent or non-violent crime were more often male, had an earlier onset of alcoholism and more withdrawal seizures and delirium tremens, and were more likely to have a history of suicide attempts. COMT genotype was not associated with a history of violent or non-violent crime. More studies are needed on the neurobiological basis of aggression and violence in alcoholism.

Neurocognitive features in male patients with schizophrenia exhibiting serious violence: a case control study

BACKGROUND

The relationship between violence and neurocognitive function in schizophrenia is unclear. We examined the backgrounds and neurocognitive functions of violent and nonviolent patients with schizophrenia to identify factors associated with serious violence.

METHODS

Thirty male patients with schizophrenia who were hospitalized after committing serious violent acts were compared with 24 hospitalized male patients with schizophrenia and no history of violence. We evaluated psychiatric symptoms using the Positive and Negative Syndrome Scale (PANSS) and neurocognitive functions using the Brief Assessment of Cognition in Schizophrenia (BACS)-Japanese version.

RESULTS

Repeated-measures analyses of variance on BACS subcomponents z-scores showed that the violent and control groups had different neuropsychological profiles at trend level (p = 0.095). Post hoc analyses of variance indicated that the violent group had significantly better working memory and executive function than the control group. In post hoc ANOVAs also controlling for the effect of the presence of substance abuse on cognitive function, violent or nonviolent group had a significant main effect on executive function but not on working memory.

CONCLUSIONS

Patient with violent or non-violent schizophrenia have distinct neuropsychological profiles. These results may help develop improved psychosocial treatments.

Brain perfusion single photon emission computed tomography in major psychiatric disorders: From basics to clinical practice

Brain single photon emission computed tomography (SPECT) is a well-established and reliable method to assess brain function through measurement of regional cerebral blood flow (rCBF). It can be used to define a patient's pathophysiological status when neurological or psychiatric symptoms cannot be explained by anatomical neuroimaging findings. Though there is ample evidence validating brain SPECT as a technique to track human behavior and correlating psychiatric disorders with dysfunction of specific brain regions, only few psychiatrists have adopted brain SPECT in routine clinical practice. It can be utilized to evaluate the involvement of brain regions in a particular patient, to individualize treatment on basis of SPECT findings, to monitor the treatment response and modify treatment, if necessary. In this article, we have reviewed the available studies in this regard from existing literature and tried to present the evidence for establishing the clinical role of brain SPECT in major psychiatric illnesses.

Deconstructing violence as a medical syndrome: mapping psychotic, impulsive, and predatory subtypes to malfunctioning brain circuits

Violence is a major management issue for forensic mental health systems. Violence can be approached as a medical syndrome and deconstructed into psychotic, impulsive, and predatory subtypes, which are hypothetically mapped onto corresponding malfunctioning brain circuits. Rational management of violence balances treatment with security, while targeting each subtype of violence with approaches unique to the psychotic, impulsive, and predatory forms of violence.

Brain white matter microstructure alterations in adolescent rhesus monkeys exposed to early life stress: associations with high cortisol during infancy

BACKGROUND

Early adverse experiences, especially those involving disruption of the mother-infant relationship, are detrimental for proper socioemotional development in primates. Humans with histories of childhood maltreatment are at high risk for developing psychopathologies including depression, anxiety, substance abuse, and behavioral disorders. However, the underlying neurodevelopmental alterations are not well understood. Here we used a nonhuman primate animal model of infant maltreatment to study the long-term effects of this early life stress on brain white matter integrity during adolescence, its behavioral correlates, and the relationship with early levels of stress hormones.

METHODS

Diffusion tensor imaging and tract based spatial statistics were used to investigate white matter integrity in 9 maltreated and 10 control animals during adolescence. Basal plasma cortisol levels collected at one month of age (when abuse rates were highest) were correlated with white matter integrity in regions with group differences. Total aggression was also measured and correlated with white matter integrity.

RESULTS

We found significant reductions in white matter structural integrity (measured as fractional anisotropy) in the corpus callosum, occipital white matter, external medullary lamina, as well as in the brainstem of adolescent rhesus monkeys that experienced maternal infant maltreatment. In most regions showing fractional anisotropy reductions, opposite effects were detected in radial diffusivity, without changes in axial diffusivity, suggesting that the alterations in tract integrity likely involve reduced myelin. Moreover, in most regions showing reduced white matter integrity, this was associated with elevated plasma cortisol levels early in life, which was significantly higher in maltreated than in control infants. Reduced fractional anisotropy in occipital white matter was also associated with increased social aggression.

CONCLUSIONS

These findings highlight the long-term impact of infant maltreatment on brain white matter structural integrity, particularly in tracts involved in visual processing, emotional regulation, and somatosensory and motor integration. They also suggest a relationship between elevations in stress hormones detected in maltreated animals during infancy and long-term brain white matter structural effects.

The Healthy Brains and Behavior Study: objectives, design, recruitment, and population coverage

Violence is increasingly viewed as a public health issue that may be ameliorated by health-based interventions. The Healthy Brains and Behavior Study (HBBS) aims to identify environmental and biological risk factors for aggression in late childhood and to reduce aggression through psychological and nutritional treatments. Utilizing a cross-disciplinary collaborative research approach, the HBBS has both human and animal components. The human component has two stages consisting of risk assessment followed by treatment. The risk assessment is based on 451 community-residing children aged 11-12 years and their caregivers, during which genetic, brain imaging, neuroendocrine, psychophysiology, environment toxicology, neurocognitive, nutrition, psychological, social and demographic risk variables are collected. Children who met criteria (N = 219) for problematic aggressive behaviors were assigned to one of four treatment groups: cognitive-behavior therapy (CBT) alone, nutritional supplements alone, both CBT and nutrition, or treatment-as-usual. Treatment duration was 12 weeks and all children whether in treatment or not were followed-up at three, six, and 12 months. The animal component assessed the effects of dietary omega-3 fatty acids on the development of aggression. This study contributes knowledge on how biological factors interact with social factors in shaping proactive and reactive aggression and assesses the efficacy of treatment approaches to reduce childhood aggression.

Structural brain alterations associated with schizophrenia preceded by conduct disorder: a common and distinct subtype of schizophrenia?

Conduct disorder (CD) prior to age 15 is a precursor of schizophrenia in a minority of cases and is associated with violent behavior through adulthood, after taking account of substance misuse. The present study used structural magnetic imaging to examine gray matter (GM) volumes among 27 men with schizophrenia preceded by CD (SZ+CD), 23 men with schizophrenia but without CD (SZ-CD), 27 men with CD only (CD), and 25 healthy (H) men. The groups with schizophrenia were similar in terms of age of onset and duration of illness, levels of psychotic symptoms, and medication. The 2 groups with CD were similar as to number of CD symptoms, lifelong aggressive behavior, and number of criminal convictions. Men with SZ+CD, relative to those with SZ-CD, displayed (1) increased GM volumes in the hypothalamus, the left putamen, the right cuneus/precuneus, and the right inferior parietal cortex after controlling for age, alcohol, and drug misuse and (2) decreased GM volumes in the inferior frontal region. Men with SZ+CD (relative to the SZ-CD group) and CD (relative to the H group) displayed increased GM volumes of the hypothalamus and the inferior and superior parietal lobes, which were not associated with substance misuse. Aggressive behavior, both prior to age 15 and lifetime tendency, was positively correlated with the GM volume of the hypothalamus. Thus, among males, SZ+CD represents a distinct subtype of schizophrenia. Although differences in behavior emerge in childhood and remain stable through adulthood, further research is needed to determine whether the differences in GM volumes result from abnormal neural development distinct from that of other males developing schizophrenia.

Neuroimaging and neurocognitive correlates of aggression and violence in schizophrenia

Individuals diagnosed with major mental disorders such as schizophrenia are more likely to have engaged in violent behavior than mentally healthy members of the same communities. Although aggressive acts can have numerous causes, research about the underlying neurobiology of violence and aggression in schizophrenia can lead to a better understanding of the heterogeneous nature of that behavior and can assist in developing new treatment strategies. The purpose of this paper is to review the recent literature and discuss some of the neurobiological correlates of aggression and violence. The focus will be on schizophrenia, and the results of neuroimaging and neuropsychological studies that have directly investigated brain functioning and/or structure in aggressive and violent samples will be discussed as well as other domains that might predispose to aggression and violence such as deficits in responding to the emotional expressions of others, impulsivity, and psychopathological symptoms. Finally gender differences regarding aggression and violence are discussed. In this context several methodological and conceptional issues that limited the comparison of these studies will be addressed.

Neurobiology of aggression and violence in schizophrenia

There is much evidence that schizophrenia patients have an increased risk for aggression and violent behavior, including homicide. The neurobiological basis and correlates of this risk have not been much studied. While genome-wide association studies are lacking, a number of candidate genes have been investigated. By far, the most intensively studied is the catechol-O-methyltransferase (COMT) gene on chromosome 22. COMT is involved in the metabolism of dopamine, a key neurotransmitter in schizophrenia pathophysiology. Several studies suggest that the Val158Met polymorphism of this gene affects COMT activity. Methionine (Met)/Met homozygote schizophrenia patients show 4- to 5-fold lower COMT activity than valine (Val)/Val homozygotes, and some but not all studies have found an association with aggression and violence. Recently, a new functional single-nucleotide polymorphism in the COMT gene, Ala72Ser, was found to be associated with homicidal behavior in schizophrenia, but this finding warrants further replication. Studies published so far indicate that an association with the monoamine oxidase A, B, or tryptophan hydroxylase 1 genes is unlikely. Data for the brain-derived neurotrophic factor gene are conflicting and limited. Data from the limited number of neuroimaging studies performed to date are interesting. Frontal and temporal lobe abnormalities are found consistently in aggressive schizophrenia patients. Positron emission tomography and single photon-emission computed tomography (SPECT) data indicate deficits also in the orbitofrontal and temporal cortex. Some functional magnetic resonance imaging studies found a negative association of violent behavior with frontal and right-sided inferior parietal activity. Neuroimaging studies may well help further elucidate the interrelationship between neurocognitive functioning, personality traits, and antisocial and violent behavior.